UV (ultraviolet) curable nail polish (including nail gel) compositions are discussed, for example, in U.S. Pat. Nos. 5,435,994 and 5,456,905, and US patent application publication nos. 2011/082228, 2011/081306, 2011/060065, 2011/182838 and 2011/274633. UV gel compositions typically consist of a layer of basecoat for adhesion on the nails, two color coats to enhance the color, and one top coat for shine. Each coating typically needs to be cured with a UV Lamp or UV LED. A UV gel system or kit typically includes a base coat composition, a color coat composition and a top coat composition.
Currently commercially available UV gels are organic solvent-based and utilize high amounts (high load) of UV curable monomer/oligomer resins as well as high loads of photo-initiators. See, for example, US 2012/199151, US 2013/034512, and U.S. Pat. No. 8,541,482. These monomer/oligomer resins and photo-initiators may cause sensitization/irritation to the nails and hands, and thus pose a safety concern to consumers. In addition, the solvents used can be damaging to the environment and thus pose also an environmental concern.
The adhesion to the nail and the cohesion among the layers of the currently available UV gel composition(s) is often very strong and difficult to remove from nails. To remove such UV gel products from nails, it is usually required to soak nails with a harsh solvent such as acetone for 10 minutes or more to effect removal. Frequent and/or prolonged use of such removal solvents in this manner can damage nails such as, for example, by making them dry and brittle. At the same time, the removal process can be time-consuming.
To overcome some of the disadvantages of the above-described solvent-based nail systems, aqueous UV-curable nail compositions have been investigated, for example, in US2012/0276028. This disclosure exemplifies high amounts of UV-curable polymer (greater than 90%). Currently, there still are no commercially-available aqueous photo-curable nail-covering products.
There remains a need for photo-curable compositions for application to nails, such as for coloring nails, that afford good wear properties, such as good adherence to nails, with less damage to the nails and the use of which is safer for the consumer and the environment.